Question

Exercise 2. Suppose there are two hosts, S and R. They are communicating over a TCP connection, and R has already received from S all bytes from 1 through 233. Now, Host S then sends three segments to Host R back to back. The segments size are 50, 70, and 90 bytes respectively. In the first segment, the source port number is 212 and the destination port number is 80. Host R sends an acknowledgement whenever it receives a segment from Host S (a) Give the sequence number, source port number, and destination port number for all the three seg- ments

Answer 1

S - R is Tcp connection. It is connection oriented network and reliable connection in proper order sender will send data to destination. Sequence number will change but sestination and source ports won't change from S to R because it is connection oriented ans reliable.

It had already sent 1 through 233 bytes nothing but 1 to 233 sequence numbers. Again S sends three segments to R so

1st Segment

Sequence number = 234 ( previous it is 233 )

Source port = 212

Destination port =80

2nd segment

Sequence number = 234+50 = 284 ( segment size is 50 bytes last byte in segment 1 is 234+50-1 =283)

Source port number =212

Destination port number = 80

3rd segment

Sequence number = 284 + 70 = 354 ( segment size is 70 bytes and 2 nd segment last byte is 284+70-1= 353)

Source port number =212

Destination port number =80